In 1991, City of Hannover, Germany
commissioned William McDonough and Michael Braungart
to develop a set of sustainability principles to guide
development associated with the EXPO 2000 World's Fair
in Hannover. The resulting document, "The
Hannover Principles - Design for Sustainability"
includes guidelines pertaining to water, which are included
below. While these guidelines were developed for the
World's Fair, they remain useful on a much broader scale.

"Water. Water is the most basic
element of life on the planetit will be celebrated
as a fundamental life-giving resource. Opportunities
to create understanding and enjoyment of water will
be encouraged throughout the design or buildings, infrastructure
and landscapes. Elements which celebrate the profound
value of this resource on both material and spiritual
levels deserve serious consideration. Designs will recognize
the communal, cultural, historical, spiritual and poetic
possibilities of the use of water and its central role
as a precondition for life.

Water use must be carefully accounted
for throughout the entire design process.

Water sources must be protected
from contamination and careful consideration given
to efficiency techniques at every step.

Potable water consumption should
only be used for life-sustaining functions.

Water from aquifers, rain water,
surface run-off water, gray water, and any water use
for sewage transport or processing systems should
all be considered within a cyclical concept.

Waste water must be returned to
the earth in a beneficial manner. Organic treatment
systems should be considered.

No ground water contamination should
result from any use of water resources related to
the construction or operation of any of the project's
facilities.

Design shall consider rainwater
and surface run-off water as a possible resource for
the inhabitants and in building systems and groundwater
systems.

Design should minimize impermeable
ground cover.

Gray water can be treated and applied
to practical or natural purposes suitable to its characteristics.

Water use in any process-related
activity shall be put back inot circulation, and toxic
chemicals or heavy metals should be minimized. All
discharges of process-related water shall meet drinking
water standards.

Water, if used for sewage treatment
or transportation, shall be restored to drinking water
standards prior to distribution or reuse."

Source: William McDonough Architects
and Michael Braungart. 1992. The Hannover Principles:
Design for Sustainability. New York: William McDonough
Architects.